I traded in my 45mm watch 5 ultra for the 47mm 6 classic and I also have a regular 40mm Watch 6 that came with the S24U. For me the Watch 5 ultra had much better battery life, giving me another day or so, but I much prefer the design of the 6 classic with the rotating bezel and it just feels and looks sleeker. I get roughly 1.5 days from it, sometimes more depending what I'm doing. The battery life of the regular Watch 6 has a little worse battery life for me than the classic but is much thinner and smaller of course so in that way may feel better at the gym etc but it really depends on what you want. Hope this helps!